The invention relates to a compact steam reformer and a method for steam reformation.
In the course of steam reforming hydrocarbons for the generation of hydrogen, the material flow for gas generation and the material flow for heating are kept separately in contrast to auto-thermal reforming. In this way the dilution of the hydrogen with nitrogen from the combustion air is avoided during steam reforming.
A compact steam reformer is known from DE 101 19 083 A1, in which the process water is essentially evaporated by means of the reformate to be cooled. The waste heat from the combustion is recovered by pre-warming the air. NOx formation is avoided by employing the flameless oxidation process. This reformer permits a rapid output regulation and has a degree of effectiveness of up to approximately 80%.
A similar reformer is known from WO 02/085781, which is optimized in respect to its exterior insulation.
These reformers meet the intended expectations. However, there is the desire for further improvements in regard to the simplification of the process regulation and the efficiency of the heat recovery. Moreover, the reformate must be relieved as much as possible of the addition of CO. This must take place so completely that downstream connected CO-sensitive fuel cells are not damaged.
It is known from EP 1 031 374 A2 to place the CO containing process gas into a so-called CO oxidator, which is simultaneously used as a reformate cooler. Cooling is achieved by evaporating the inflowing process gas in an evaporator.
Based on the foregoing, it is the object of the invention to improve the compact steam reformer mentioned at the outset in regard to the conduct of the process and the efficiency of the heat recovery.
This object is attained by means of the compact steam reformer in accordance with the invention as hereinafter described.